The ratio of the specific heats of nitrogen and of oxygen

Abstract

The investigation of the ratio of the specific heats, c p / c v = γ , of nitrogen and oxygen described in the following paper was undertaken by a method substantially the same as that used previously with air and carbon dioxide, and described in an earlier communication. This consists in measuring the fall in temperature which occurs when a large volume of the gas is allowed to expand adiabatically. If a vessel filled with the gas at a pressure p 1 , slightly greater than atmospheric, is put into communication with the free air, at a pressure p 2 , by suitable means, so that the equalisation of pressures occurs as nearly as possible adiabatically, and if T 1 and T 2 are the absolute temperature of the gas before and after expansion, then, for an ideal gas , it is known that γ = c p /c v = log p 1 - log p 2 /(log p 1 - log p 2 ) - (log T 1 - log T 2 ) (1) Before considering the details of the method used in the present research reference may be made to the experiments of Mercer, in 1914, and of Shields, in 1917, supplementing the work discussed in the previous communication.